Previously: Mainstream Nutrition Science on Obesity

Edit: In retrospect, I think it maybe should have combined this post with part 3. Unfortunately, the problem of what to do with existing comments makes that hard to fix now.

Taubes first made a name for himself as a low-carb advocate in 2002 with a New York Times article titled "What if It's All Been a Big Fat Lie?" When I first read this article, I was getting extremely suspicious by the second paragraph (emphasis added):

If the members of the American medical establishment were to have a collective find-yourself-standing-naked-in-Times-Square-type nightmare, this might be it. They spend 30 years ridiculing Robert Atkins, author of the phenomenally-best-selling ''Dr. Atkins' Diet Revolution'' and ''Dr. Atkins' New Diet Revolution,'' accusing the Manhattan doctor of quackery and fraud, only to discover that the unrepentant Atkins was right all along. Or maybe it's this: they find that their very own dietary recommendations -- eat less fat and more carbohydrates -- are the cause of the rampaging epidemic of obesity in America. Or, just possibly this: they find out both of the above are true.

When Atkins first published his ''Diet Revolution'' in 1972, Americans were just coming to terms with the proposition that fat -- particularly the saturated fat of meat and dairy products -- was the primary nutritional evil in the American diet. Atkins managed to sell millions of copies of a book promising that we would lose weight eating steak, eggs and butter to our heart's desire, because it was the carbohydrates, the pasta, rice, bagels and sugar, that caused obesity and even heart disease. Fat, he said, was harmless.

Atkins allowed his readers to eat ''truly luxurious foods without limit,'' as he put it, ''lobster with butter sauce, steak with béarnaise sauce . . . bacon cheeseburgers,'' but allowed no starches or refined carbohydrates, which means no sugars or anything made from flour. Atkins banned even fruit juices, and permitted only a modicum of vegetables, although the latter were negotiable as the diet progressed.

It's one thing to claim that, all else equal, low-carb diets have advantages over low-fat diets. It's another thing to claim you can eat unlimited amounts of fatty foods without gaining weight.

I'd heard of Atkins before but didn't know much about him. I got curious to know more about the man Taubes was casting as the hero who just may have been "right all along," so I popped over to the Wikipedia article on the diet, which says:

Many people believe that the Atkins Diet promotes eating unlimited amounts of fatty meats and cheeses. This was allowed and promoted in early editions of the book. In the newest revision, not written by the now deceased Dr. Atkins, this is not promoted. The Atkins Diet does not impose caloric restriction, or definite limits on proteins, with Atkins saying in his book that this plan is "not a license to gorge," but rather that eating protein until satiated is promoted. The director of research and education for Atkins Nutritionals, Collette Heimowitz, has said, "The media and opponents of Atkins often sensationalise and simplify the diet as the all-the-steak-you-can-eat diet. This has never been true". However, this new approach by Atkins Nutritionals is often at odds with the earlier writings of Dr. Atkins.

The last sentence of this paragraph is helpfully marked "citation needed," leaving an unresolved conflict between whatever Wikipedia editor wrote the paragraph and what the Atkins folks (at least now) claim. I ordered a used copy of the original 1972 edition of Atkins' book through Amazon, and what I found supports the Wikipedia editor. The folks currently in charge of Atkins Nutritionals are white-washing.

The sensational "truly luxurious food without limit" quote in Taubes' article, for example, can be found on page 15 and comes with no context that would make it more reasonable. In fact, lest anyone misunderstand it, it's followed by a statement that "As long as you don't take in carbohydrates, you can eat any amount of this 'fattening' food and it won't put a single ounce of fat on you." (In the book, this is italicized for emphasis.)

Atkins acknowledged that most of the people who used his diet ended up eating less overall, but claimed that some of his patients had lost significant amounts of weight eating 3,000 calories per day or more. In one case, Atkins claimed, a man had lost fifty pounds on a diet of 5,000 calories per day. He attempted to explain this by invoking the fact that extremely low-carbohydrate diets will cause people to excrete ketones (which Atkins referred to as "incompletely burned calories") in their urine. However, as a statement on the Atkins diet put out by the American Medical Association explains:

When ketone excretion incident to such diets has actually been measured, it has been found to range between 0.5 and 10 gm/24 hr. Studies carried out on starving nondieabetic persons indicate that at most about 20 gm of ketones per day may be excreted in the urine. And, as Folin and Denis have show, the total acetone excretion with the breath is quantitatively insignificant; at most, 1 gm/day. Since caloric value of Ketones is about 4.5 kcal/gm, it is clear that, in subjects on ketogenic diets, ketone losses in the urine rarely, if ever, exceed 100 kcal/day, a quantity that could not possibly account for the dramatic results claimed for such diets.

As far as I can tell, nobody today defends Atkins' original "ketones in the urine" explanation for how his diet supposedly works. It's not entirely clear to me what was going on with the patients Atkins claimed lost weight on a high-calorie diet, but it wouldn't be surprising if a minority of his patients had simply misjudged their caloric intake. In spite of this, Taubes still appears to want to defend Atkins' most extreme claims about people being able to eat unlimited fat without gaining weight.

This isn't entirely obvious when you read his books Good Calories, Bad Calories or Why We Get Fat, which go for a slightly less sensational presentation than the Times article. Nevertheless, in the epilogue to Good Calories, Bad Calories, he claims that "Dietary fat, whether saturated or not, is not a cause of obesity, heart disease, or any other chronic disease of civilization." There's a sense in which that claim might be somewhat plausible, if he meant that it's total calories, not fat per se, that's the main culprit in all those problems. But Taubes also puts a lot of energy (no pun intended) into attacking the mainstream emphasis on calories. 

Why We Get Fat, for example, contains claims such as:

[A 1965 New York Times article claimed that] "It is a medical fact that no dieter can lose weight unless he cuts down on excess calories, either by taking in fewer of them, or by burning them up." We now know that this is not a medical fact, but the nutritionists didn't in 1965, and most of them still don't. (p. 161)

But we know now what happens when we restrict carbohydrates, and why this leads to weight loss and particularly fat loss, independent of the calories we consume from dietary fat and protein... If you restrict only carbohydrates, you can always eat more protein and fat if you feel the urge, since they have no effect on fat accumulation. (p. 174)

No effect? That's a strong claim. And as we'll see in the next two posts, Taubes' evidence for this claim ends up consisting largely on a series of misrepresentations of mainstream nutrition science, which allow him to present his views as the only alternative once he's knocked down his straw men.